Fish Movements and Passage Through a Water Control Structure: River Stage and Floodplain Connectivityhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2901Fish Movements and Passage Through a Water Control Structure: River Stage and Floodplain ConnectivityS. Tripp, K. Jack Killgore, J. E. Garvey2015-03-30T13:15:54.829841-05:00doi:10.1002/rra.2901John Wiley & Sons, Inc.10.1002/rra.2901http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2901Short Communicationn/an/aAbstract

Previous methods for constructing univariate habitat suitability criteria (HSC) curves have ranged from professional judgement to kernel-smoothed density functions or combinations thereof. We present a new method of generating HSC curves that applies probability density functions as the mathematical representation of the curves. Compared with previous approaches, benefits of our method include (1) estimation of probability density function parameters directly from raw data, (2) quantitative methods for selecting among several candidate probability density functions, and (3) concise methods for expressing estimation uncertainty in the HSC curves. We demonstrate our method with a thorough example using data collected on the depth of water used by juvenile Chinook salmon (Oncorhynchus tschawytscha) in the Klamath River of northern California and southern Oregon. All R code needed to implement our example is provided in the appendix. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

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Previous methods for constructing univariate habitat suitability criteria (HSC) curves have ranged from professional judgement to kernel-smoothed density functions or combinations thereof. We present a new method of generating HSC curves that applies probability density functions as the mathematical representation of the curves. Compared with previous approaches, benefits of our method include (1) estimation of probability density function parameters directly from raw data, (2) quantitative methods for selecting among several candidate probability density functions, and (3) concise methods for expressing estimation uncertainty in the HSC curves. We demonstrate our method with a thorough example using data collected on the depth of water used by juvenile Chinook salmon (Oncorhynchus tschawytscha) in the Klamath River of northern California and southern Oregon. All R code needed to implement our example is provided in the appendix. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.Trade-Offs in Seed Dispersal Strategies Across Riparian Trees: The How Matters as Much as the Whenhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2899Trade-Offs in Seed Dispersal Strategies Across Riparian Trees: The How Matters as Much as the WhenE. González, B. Bourgeois, A. Masip, A. A. Sher2015-03-27T16:48:01.269774-05:00doi:10.1002/rra.2899John Wiley & Sons, Inc.10.1002/rra.2899http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2899Research Articlen/an/aAbstract

The effectiveness of agricultural conservation programmes to adequately reduce nutrient exports to receiving streams and to help limit downstream hypoxia issues remains a concern. Quantifying programme success can be difficult given that short-term basin changes may be masked by long-term water-quality shifts. We evaluated nutrient export at stream sites in the 44 months that followed a period of increased, integrated conservation implementation within the Lower Grand River Basin. These short-term responses were then compared with export that occurred in the main stem and adjacent rivers in northern Missouri over a 22-year period to better contextualize any recent changes. Results indicate that short-term (October 2010 through May 2014) total nitrogen (TN) concentrations in the Grand River were 20% less than the long-term average, and total phosphorus (TP) concentrations were 23% less. Nutrient reductions in the short term were primarily the result of the less-than-average precipitation and, consequently, streamflow that was 36% below normal. Therefore, nutrient concentrations measured in tributary streams were likely less than normal during the implementation period. Northern Missouri streamflow-normalized TN concentrations remained relatively flat or declined over the period 1991 through 2013 likely because available sources of nitrogen, determined as the sum of commercial fertilizers, available animal manures and atmospheric inputs, were typically less than crop requirement for much of that time frame. Conversely, flow-normalized stream TP concentrations increased over the past 22 years in northern Missouri streams, likely in response to many years of phosphorus inputs in excess of crop requirements. Stream nutrient changes were most pronounced during periods that coincided with the major tillage, planting and growth phases of row crops and increased streamflow. Nutrient reduction strategies targeted at the period February through June would likely have the greatest impact on reducing nutrient export from the basin. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

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The effectiveness of agricultural conservation programmes to adequately reduce nutrient exports to receiving streams and to help limit downstream hypoxia issues remains a concern. Quantifying programme success can be difficult given that short-term basin changes may be masked by long-term water-quality shifts. We evaluated nutrient export at stream sites in the 44 months that followed a period of increased, integrated conservation implementation within the Lower Grand River Basin. These short-term responses were then compared with export that occurred in the main stem and adjacent rivers in northern Missouri over a 22-year period to better contextualize any recent changes. Results indicate that short-term (October 2010 through May 2014) total nitrogen (TN) concentrations in the Grand River were 20% less than the long-term average, and total phosphorus (TP) concentrations were 23% less. Nutrient reductions in the short term were primarily the result of the less-than-average precipitation and, consequently, streamflow that was 36% below normal. Therefore, nutrient concentrations measured in tributary streams were likely less than normal during the implementation period. Northern Missouri streamflow-normalized TN concentrations remained relatively flat or declined over the period 1991 through 2013 likely because available sources of nitrogen, determined as the sum of commercial fertilizers, available animal manures and atmospheric inputs, were typically less than crop requirement for much of that time frame. Conversely, flow-normalized stream TP concentrations increased over the past 22 years in northern Missouri streams, likely in response to many years of phosphorus inputs in excess of crop requirements. Stream nutrient changes were most pronounced during periods that coincided with the major tillage, planting and growth phases of row crops and increased streamflow. Nutrient reduction strategies targeted at the period February through June would likely have the greatest impact on reducing nutrient export from the basin. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.Assessing Juvenile Native Fish Demographic Responses to a Steady Flow Experiment in a Large Regulated Riverhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2893Assessing Juvenile Native Fish Demographic Responses to a Steady Flow Experiment in a Large Regulated RiverC. Finch, W. E. Pine, C. B. Yackulic, M. J. Dodrill, M. Yard, B. S. Gerig, L. G. Coggins, J. Korman2015-03-12T22:18:43.786122-05:00doi:10.1002/rra.2893John Wiley & Sons, Inc.10.1002/rra.2893http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2893Research Articlen/an/aAbstract

It is hypothesized that slow, shallow water habitats benefit larval pallid sturgeon Scaphirhynchus albus; however, testing this hypothesis is difficult, given the low number of larval pallid sturgeon present in large rivers. In contrast, relatively large numbers of age-0 shovelnose sturgeon Scaphirhynchus platorynchus have been sampled, providing a potentially useful baseline to assess the importance of slow, shallow water to age-0 sturgeon of both species (hereafter age-0 sturgeon) in the lower Missouri River. Thus, we investigated the potential relationships between the prevalence of shallow water <1.5 m and the age-0 sturgeon catch rates at multiple scales. Age-0 sturgeon were usually sampled in water >1.5 m, and catch rates were usually highest in the upper half [i.e. river kilometre (RKM) 400 to 800] of the lower Missouri River study area, whereas the availability of water <1.5 m was usually highest in the lower half (i.e. RKM 0 to 400). Similarly, there was no relationship between age-0 sturgeon mean catch-per-unit effort and ha/km of water <1.5 m at any studied scale. Our results may suggest that shallow water, as currently defined, may not be a suitable surrogate for assessing efforts to address pallid sturgeon population declines. However, it is still unknown if lack of appropriate habitat is currently limiting pallid sturgeon. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. River Research and Applications published by John Wiley & Sons Ltd.

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It is hypothesized that slow, shallow water habitats benefit larval pallid sturgeon Scaphirhynchus albus; however, testing this hypothesis is difficult, given the low number of larval pallid sturgeon present in large rivers. In contrast, relatively large numbers of age-0 shovelnose sturgeon Scaphirhynchus platorynchus have been sampled, providing a potentially useful baseline to assess the importance of slow, shallow water to age-0 sturgeon of both species (hereafter age-0 sturgeon) in the lower Missouri River. Thus, we investigated the potential relationships between the prevalence of shallow water <1.5 m and the age-0 sturgeon catch rates at multiple scales. Age-0 sturgeon were usually sampled in water >1.5 m, and catch rates were usually highest in the upper half [i.e. river kilometre (RKM) 400 to 800] of the lower Missouri River study area, whereas the availability of water <1.5 m was usually highest in the lower half (i.e. RKM 0 to 400). Similarly, there was no relationship between age-0 sturgeon mean catch-per-unit effort and ha/km of water <1.5 m at any studied scale. Our results may suggest that shallow water, as currently defined, may not be a suitable surrogate for assessing efforts to address pallid sturgeon population declines. However, it is still unknown if lack of appropriate habitat is currently limiting pallid sturgeon. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. River Research and Applications published by John Wiley & Sons Ltd.Evaluation of Steelhead Passage Flows Using Hydraulic Modeling on an Unregulated Coastal California Riverhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2884Evaluation of Steelhead Passage Flows Using Hydraulic Modeling on an Unregulated Coastal California RiverR. W. Holmes, D. E. Rankin, E. Ballard, M. Gard2015-03-12T05:43:39.868175-05:00doi:10.1002/rra.2884John Wiley & Sons, Inc.10.1002/rra.2884http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2884Research Articlen/an/aAbstract

Passage and habitat connectivity flows for steelhead Oncorhynchus mykiss through depth sensitive natural, low gradient, critical riffle sites were investigated in the unregulated Big Sur River, California. The River2D two-dimensional hydraulic habitat model, along with quantitative passage metrics and species-specific and lifestage-specific depth criteria, were used to evaluate and compare predicted fish passage flows with flows derived by a traditional empirical critical riffle fish passage method. Passage flows were also compared with historical unimpaired natural hydrology patterns to assess the frequency and duration of suitable passage flows under the naturally variable flow regimes characteristic of Central California coastal rivers. A strong relationship (r2 = 0.93) was observed between flows predicted by hydraulic modeling and flows identified by the empirical critical riffle method. River2D provided validation that the flows derived using the traditional critical riffle methodology provided for contiguous passable pathways of suitable hydraulic (depth and velocity) conditions through complex cobble-dominated riffle sites. Furthermore, steelhead passage flows were spatially and temporally consistent between lagoon and upstream riffles for adults, and were generally indicative of a river system in equilibrium with a naturally variable flow regime and associated intact ecological processes. An analysis of 25 years of continuous flow data indicated sufficient flows for upstream passage by young-of-year and juvenile steelhead were produced between 37% and 100% and between 1% and 95% of the time, respectively. September and October are the most challenging months for natural flows to meet young-of-year and juvenile passage and habitat connectivity flows. Careful consideration of seasonal and interannual flow variability dynamics, therefore, are critical components of an effective flow management strategy for the maintenance and protection of passage and habitat connectivity flows between lagoon and upriver habitats. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

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Passage and habitat connectivity flows for steelhead Oncorhynchus mykiss through depth sensitive natural, low gradient, critical riffle sites were investigated in the unregulated Big Sur River, California. The River2D two-dimensional hydraulic habitat model, along with quantitative passage metrics and species-specific and lifestage-specific depth criteria, were used to evaluate and compare predicted fish passage flows with flows derived by a traditional empirical critical riffle fish passage method. Passage flows were also compared with historical unimpaired natural hydrology patterns to assess the frequency and duration of suitable passage flows under the naturally variable flow regimes characteristic of Central California coastal rivers. A strong relationship (r2 = 0.93) was observed between flows predicted by hydraulic modeling and flows identified by the empirical critical riffle method. River2D provided validation that the flows derived using the traditional critical riffle methodology provided for contiguous passable pathways of suitable hydraulic (depth and velocity) conditions through complex cobble-dominated riffle sites. Furthermore, steelhead passage flows were spatially and temporally consistent between lagoon and upstream riffles for adults, and were generally indicative of a river system in equilibrium with a naturally variable flow regime and associated intact ecological processes. An analysis of 25 years of continuous flow data indicated sufficient flows for upstream passage by young-of-year and juvenile steelhead were produced between 37% and 100% and between 1% and 95% of the time, respectively. September and October are the most challenging months for natural flows to meet young-of-year and juvenile passage and habitat connectivity flows. Careful consideration of seasonal and interannual flow variability dynamics, therefore, are critical components of an effective flow management strategy for the maintenance and protection of passage and habitat connectivity flows between lagoon and upriver habitats. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.Diel Activity Patterns of Juvenile Late Fall-run Chinook Salmon with Implications for Operation of a Gated Water Diversion in the Sacramento–San Joaquin River Deltahttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2885Diel Activity Patterns of Juvenile Late Fall-run Chinook Salmon with Implications for Operation of a Gated Water Diversion in the Sacramento–San Joaquin River DeltaJ. M. Plumb, N. S. Adams, R. W. Perry, C. M. Holbrook, J. G. Romine, A. R. Blake, J. R. Burau2015-03-12T05:41:48.529341-05:00doi:10.1002/rra.2885John Wiley & Sons, Inc.10.1002/rra.2885http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2885Research Articlen/an/aAbstract

In the Sacramento–San Joaquin River Delta, California, tidal forces that reverse river flows increase the proportion of water and juvenile late fall-run Chinook salmon diverted into a network of channels that were constructed to support agriculture and human consumption. This area is known as the interior delta, and it has been associated with poor fish survival. Under the rationale that the fish will be diverted in proportion to the amount of water that is diverted, the Delta Cross Channel (DCC) has been prescriptively closed during the winter out-migration to reduce fish entrainment and mortality into the interior delta. The fish are thought to migrate mostly at night, and so daytime operation of the DCC may allow for water diversion that minimizes fish entrainment and mortality. To assess this, the DCC gate was experimentally opened and closed while we released 2983 of the fish with acoustic transmitters upstream of the DCC to monitor their arrival and entrainment into the DCC. We used logistic regression to model night-time arrival and entrainment probabilities with covariates that included the proportion of each diel period with upstream flow, flow, rate of change in flow and water temperature. The proportion of time with upstream flow was the most important driver of night-time arrival probability, yet river flow had the largest effect on fish entrainment into the DCC. Modelling results suggest opening the DCC during daytime while keeping the DCC closed during night-time may allow for water diversion that minimizes fish entrainment into the interior delta. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

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In the Sacramento–San Joaquin River Delta, California, tidal forces that reverse river flows increase the proportion of water and juvenile late fall-run Chinook salmon diverted into a network of channels that were constructed to support agriculture and human consumption. This area is known as the interior delta, and it has been associated with poor fish survival. Under the rationale that the fish will be diverted in proportion to the amount of water that is diverted, the Delta Cross Channel (DCC) has been prescriptively closed during the winter out-migration to reduce fish entrainment and mortality into the interior delta. The fish are thought to migrate mostly at night, and so daytime operation of the DCC may allow for water diversion that minimizes fish entrainment and mortality. To assess this, the DCC gate was experimentally opened and closed while we released 2983 of the fish with acoustic transmitters upstream of the DCC to monitor their arrival and entrainment into the DCC. We used logistic regression to model night-time arrival and entrainment probabilities with covariates that included the proportion of each diel period with upstream flow, flow, rate of change in flow and water temperature. The proportion of time with upstream flow was the most important driver of night-time arrival probability, yet river flow had the largest effect on fish entrainment into the DCC. Modelling results suggest opening the DCC during daytime while keeping the DCC closed during night-time may allow for water diversion that minimizes fish entrainment into the interior delta. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.Scaling Down Habitat Selection by Large River Fishes to Understand Patterns Relevant to Individualshttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2883Scaling Down Habitat Selection by Large River Fishes to Understand Patterns Relevant to IndividualsW. D. Hintz, G. T. Grimes, J. E. Garvey2015-03-06T08:10:52.645476-05:00doi:10.1002/rra.2883John Wiley & Sons, Inc.10.1002/rra.2883http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2883Research Articlen/an/aABSTRACT

The occurrence of aquatic plants was analysed in a medium-sized river in Greece. There were three objectives. The first was to examine the macrophyte assemblage structure along the river. The identification and hierarchical structure of aquatic plant assemblages were analyzed using Bray–Curtis analysis. Taxa primarily responsible for the differences among the assemblages were identified using similarity percentage analysis. The second objective was to investigate whether habitat features have greater impact on aquatic plant assemblages than chemical parameters. Partial canonical correspondence analysis was used for partitioning the total variation of the biological response. The third objective was to further explore the relationships between hydrophytes (water-supported plants) richness and water quality using linear regression model.

Recruitment of European eels (Anguilla anguilla) has declined to the extent that they have been added to the IUCN Red List of Threatened Species. Therefore, it is critical to ensure that eels complete their outward river migration in order to contribute to the available spawning stock. We conducted a 4-year (2007–2011) telemetry study to understand the migratory behaviour and potential impact of environmental factors on the eel during this critical life stage.

Out of 399 female eels tagged with acoustic transmitters, only 28% demonstrated clear downstream migratory behaviour. Fifty-five percent were detected exhibiting no downstream migration behaviour and 17% were not detected at any monitoring station. Movement patterns of downstream-migrating (silver) eels were characterized by nocturnal activity and seasonal migration, with distinct peaks in autumn and spring. Migration was often discontinuous and exhibited phases of active locomotion and expanded stopovers. The most important determinants of movement activity were water temperature, cumulative precipitation and moonlight, although the significance varied by season and location in the river basin.

The mesoscale (100–102 m) of river habitats has been identified as the scale that simultaneously offers insights into ecological structure and falls within the practical bounds of river management. Mesoscale habitat (mesohabitat) classifications for relatively large rivers, however, are underdeveloped compared with those produced for smaller streams. Approaches to habitat modelling have traditionally focused on individual species or proceeded on a species-by-species basis. This is particularly problematic in larger rivers where the effects of biological interactions are more complex and intense. Community-level approaches can rapidly model many species simultaneously, thereby integrating the effects of biological interactions while providing information on the relative importance of environmental variables in structuring the community. One such community-level approach, multivariate regression trees, was applied in order to determine the relative influences of abiotic factors on fish assemblages within shoreline mesohabitats of San Pedro River, Chile, and to define reference communities prior to the planned construction of a hydroelectric power plant.

Ecologists estimate vital rates, such as growth and survival, to better understand population dynamics and identify sensitive life history parameters for species or populations of concern. Here, we assess spatiotemporal variation in growth, movement, density, and survival of subadult humpback chub living in the Little Colorado River, Grand Canyon, AZ from 2001–2002 and 2009–2013. We divided the Little Colorado River into three reaches and used a multistate mark-recapture model to determine rates of movement and differences in survival and density between sites for different cohorts. Additionally, site-specific and year-specific effects on growth were evaluated using a linear model. Results indicate that summer growth was higher for upstream sites compared with downstream sites. In contrast, there was not a consistent spatial pattern across years in winter growth; however, river-wide winter growth was negatively related to the duration of floods from 1 October to 15 May. Apparent survival was estimated to be lower at the most downstream site compared with the upstream sites; however, this could be because in part of increased emigration into the Colorado River at downstream sites. Furthermore, the 2010 cohort (i.e. fish that are age 1 in 2010) exhibited high apparent survival relative to other years. Movement between reaches varied with year, and some years exhibited preferential upstream displacement. Improving understanding of spatiotemporal effects on age 1 humpback chub survival can help inform current management efforts to translocate humpback chub into new locations and give us a better understanding of the factors that may limit this tributary's carrying capacity for humpback chub. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

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Ecologists estimate vital rates, such as growth and survival, to better understand population dynamics and identify sensitive life history parameters for species or populations of concern. Here, we assess spatiotemporal variation in growth, movement, density, and survival of subadult humpback chub living in the Little Colorado River, Grand Canyon, AZ from 2001–2002 and 2009–2013. We divided the Little Colorado River into three reaches and used a multistate mark-recapture model to determine rates of movement and differences in survival and density between sites for different cohorts. Additionally, site-specific and year-specific effects on growth were evaluated using a linear model. Results indicate that summer growth was higher for upstream sites compared with downstream sites. In contrast, there was not a consistent spatial pattern across years in winter growth; however, river-wide winter growth was negatively related to the duration of floods from 1 October to 15 May. Apparent survival was estimated to be lower at the most downstream site compared with the upstream sites; however, this could be because in part of increased emigration into the Colorado River at downstream sites. Furthermore, the 2010 cohort (i.e. fish that are age 1 in 2010) exhibited high apparent survival relative to other years. Movement between reaches varied with year, and some years exhibited preferential upstream displacement. Improving understanding of spatiotemporal effects on age 1 humpback chub survival can help inform current management efforts to translocate humpback chub into new locations and give us a better understanding of the factors that may limit this tributary's carrying capacity for humpback chub. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.IMPROVING ANN-BASED SHORT-TERM AND LONG-TERM SEASONAL RIVER FLOW FORECASTING WITH SIGNAL PROCESSING TECHNIQUEShttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2865IMPROVING ANN-BASED SHORT-TERM AND LONG-TERM SEASONAL RIVER FLOW FORECASTING WITH SIGNAL PROCESSING TECHNIQUESH. Badrzadeh, R. Sarukkalige, A. W. Jayawardena2014-12-20T01:06:33.010694-05:00doi:10.1002/rra.2865John Wiley & Sons, Inc.10.1002/rra.2865http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2865Research Articlen/an/aABSTRACT

Natural flow regimes represent the hydrologic conditions to which native aquatic organisms are best adapted. We completed a regional river classification and quantitative descriptions of each natural flow regime for the Ozark–Ouachita Interior Highlands region of Arkansas, Missouri and Oklahoma. On the basis of daily flow records from 64 reference streams, seven natural flow regimes were identified with mixture model cluster analysis: Groundwater Stable, Groundwater, Groundwater Flashy, Perennial Runoff, Runoff Flashy, Intermittent Runoff and Intermittent Flashy. Sets of flow metrics were selected that best quantified nine ecologically important components of these natural flow regimes. An uncertainty analysis was performed to avoid selecting metrics strongly affected by measurement uncertainty that can result from short periods of record. Measurement uncertainties (bias, precision and accuracy) were assessed for 170 commonly used flow metrics. The ranges of variability expected for select flow metrics under natural conditions were quantified for each flow regime to provide a reference for future assessments of hydrologic alteration. A random forest model was used to predict the natural flow regimes of all stream segments in the study area based on climate and catchment characteristics, and a map was produced. The geographic distribution of flow regimes suggested distinct ecohydrological regions that may be useful for conservation planning. This project provides a hydrologic foundation for future examination of flow–ecology relationships in the region. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

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Natural flow regimes represent the hydrologic conditions to which native aquatic organisms are best adapted. We completed a regional river classification and quantitative descriptions of each natural flow regime for the Ozark–Ouachita Interior Highlands region of Arkansas, Missouri and Oklahoma. On the basis of daily flow records from 64 reference streams, seven natural flow regimes were identified with mixture model cluster analysis: Groundwater Stable, Groundwater, Groundwater Flashy, Perennial Runoff, Runoff Flashy, Intermittent Runoff and Intermittent Flashy. Sets of flow metrics were selected that best quantified nine ecologically important components of these natural flow regimes. An uncertainty analysis was performed to avoid selecting metrics strongly affected by measurement uncertainty that can result from short periods of record. Measurement uncertainties (bias, precision and accuracy) were assessed for 170 commonly used flow metrics. The ranges of variability expected for select flow metrics under natural conditions were quantified for each flow regime to provide a reference for future assessments of hydrologic alteration. A random forest model was used to predict the natural flow regimes of all stream segments in the study area based on climate and catchment characteristics, and a map was produced. The geographic distribution of flow regimes suggested distinct ecohydrological regions that may be useful for conservation planning. This project provides a hydrologic foundation for future examination of flow–ecology relationships in the region. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.POPULATION TRENDS, BEND USE RELATIVE TO AVAILABLE HABITAT AND WITHIN-RIVER-BEND HABITAT USE OF EIGHT INDICATOR SPECIES OF MISSOURI AND LOWER KANSAS RIVER BENTHIC FISHES: 15 YEARS AFTER BASELINE ASSESSMENThttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2846POPULATION TRENDS, BEND USE RELATIVE TO AVAILABLE HABITAT AND WITHIN-RIVER-BEND HABITAT USE OF EIGHT INDICATOR SPECIES OF MISSOURI AND LOWER KANSAS RIVER BENTHIC FISHES: 15 YEARS AFTER BASELINE ASSESSMENTM. L. Wildhaber, W.-H. Yang, A. Arab2014-11-04T04:09:42.782254-05:00doi:10.1002/rra.2846John Wiley & Sons, Inc.10.1002/rra.2846http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2846Research Articlen/an/aABSTRACT

Presented in this paper is a hydraulic model that combines a rational regime theory with an at-a-station hydraulic geometry simulator (ASHGS) to predict reach-averaged hydraulic conditions for flows up to but not exceeding the bankfull stage. The hydraulic conditions determined by ASHGS can be paired with an empirical joint frequency distribution equation and applicable habitat suitability indices to generate weighted usable area (WUA) as a function of flow. ASHGS was tested against a 2-dimensional hydrodynamic model (River2D) of a mid-size channel in the Interior Region of British Columbia. By linking ASHGS to a regime model, it becomes possible to evaluate the direction and magnitude of habitat changes associated with a wide range of environmental changes. Our regime model considers flow regime, sediment supply, and riparian vegetation: these governing variables can be used to simulate responses to forest fire, flow regulation and changes in climate and land use. Practitioners can examine ‘what-if’ scenarios that otherwise would be too expensive and time consuming to fully explore. The model boundaries of commonly used data-intensive hydraulic habitat models (e.g. PHABSIM) are not easily adjusted and such models are not designed to estimate future morphological and hydraulic habitat conditions in rivers the undergo significant channel restructuring. The proposed model has the potential to become an accepted flow assessment tool amongst practitioners due to modest data requirements, user-friendliness, and large spatial applicability; it can be used to conduct preliminary assessments of channel altering projects and determine if in-depth habitat assessments are justified.

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Presented in this paper is a hydraulic model that combines a rational regime theory with an at-a-station hydraulic geometry simulator (ASHGS) to predict reach-averaged hydraulic conditions for flows up to but not exceeding the bankfull stage. The hydraulic conditions determined by ASHGS can be paired with an empirical joint frequency distribution equation and applicable habitat suitability indices to generate weighted usable area (WUA) as a function of flow. ASHGS was tested against a 2-dimensional hydrodynamic model (River2D) of a mid-size channel in the Interior Region of British Columbia. By linking ASHGS to a regime model, it becomes possible to evaluate the direction and magnitude of habitat changes associated with a wide range of environmental changes. Our regime model considers flow regime, sediment supply, and riparian vegetation: these governing variables can be used to simulate responses to forest fire, flow regulation and changes in climate and land use. Practitioners can examine ‘what-if’ scenarios that otherwise would be too expensive and time consuming to fully explore. The model boundaries of commonly used data-intensive hydraulic habitat models (e.g. PHABSIM) are not easily adjusted and such models are not designed to estimate future morphological and hydraulic habitat conditions in rivers the undergo significant channel restructuring. The proposed model has the potential to become an accepted flow assessment tool amongst practitioners due to modest data requirements, user-friendliness, and large spatial applicability; it can be used to conduct preliminary assessments of channel altering projects and determine if in-depth habitat assessments are justified.AN ESTIMATE OF BASIN-WIDE DENITRIFICATION BASED ON FLOODPLAIN INUNDATION IN THE ATCHAFALAYA RIVER BASIN, LOUISIANAhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2854AN ESTIMATE OF BASIN-WIDE DENITRIFICATION BASED ON FLOODPLAIN INUNDATION IN THE ATCHAFALAYA RIVER BASIN, LOUISIANAM. G. Bennett, K. A. Fritz, A. Hayden-Lesmeister, J. P. Kozak, A. Nickolotsky2014-10-22T02:12:42.284128-05:00doi:10.1002/rra.2854John Wiley & Sons, Inc.10.1002/rra.2854http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2854Research Articlen/an/aABSTRACT

Imaging spectroscopy is used in this work as an essential mapping tool to monitor changes in contaminated river sediments. Multidate hyperspectral image data (HyMap) are utilized to identify spatial mineral patterns, to detect temporal changes in mineralogy and to link these changes with geochemical processes and short-term climate characteristics.

River sediments contaminated by acid mine drainage are covered by crusts with variably hydrated iron sulphate. The mineralogy of the crusts and the grain size of the underlying fluvial sediments overlap. The spectra used to build up maps from HyMap data are diagnosed mineralogically with archive spectral libraries from pyrite oxidation minerals from well-known sequences of minerals.

The maps compiled from hyperspectral imagery display generalized oxidation shown by the coatings over river sediments following warm and dry periods with low water level. After the wet periods, the area covered by oxidized mineralogical phases recedes in favour of hydrated sulphate.

The Missouri River has been extensively altered as the result of channelization, bank stabilization, and the construction of six main stem reservoirs. In response to the resultant habitat loss, the US Army Corps of Engineers was tasked with restoring approximately 8100 ha of shallow water habitat (SWH), in part, for the benefit of the endangered pallid sturgeon (Scaphirhynchus albus). Construction of off-channel habitats involves the removal and disposal of excavated alluvium either by direct discharge into the river or by secondary erosion, which raised concerns regarding the introduction of sediment and associated nutrients into the Missouri River.

Soils from nine side-channel chutes were sampled to represent nutrient concentrations from habitat restoration activities. Soils from 12 historically undisturbed sites were also sampled to represent reference conditions in the Missouri River flood plain. The results of this study indicate that nutrient characteristics of soils from selected SWH locations generally are similar to those of historically undisturbed soils. The estimated mass of total phosphorus from chutes accounted for 1.9% of Missouri River and 0.5% of Mississippi River total phosphorus loads during the 1993–2012 analysis period. The mass of nitrate, the constituent most closely related to gulf hypoxia, was 0.01% or less of the Missouri and Mississippi River nitrate loads. Sediment volumes from the chutes accounted for 3.1 and 1.5% of total suspended loads from the Missouri and Mississippi Rivers. Overall, the introduced sediment from side-channel chute construction associated with SWH restoration accounts for a small portion of total nutrient and sediment transport in the Missouri and Mississippi Rivers. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. River Research and Applications published by John Wiley & Sons, Ltd.

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The Missouri River has been extensively altered as the result of channelization, bank stabilization, and the construction of six main stem reservoirs. In response to the resultant habitat loss, the US Army Corps of Engineers was tasked with restoring approximately 8100 ha of shallow water habitat (SWH), in part, for the benefit of the endangered pallid sturgeon (Scaphirhynchus albus). Construction of off-channel habitats involves the removal and disposal of excavated alluvium either by direct discharge into the river or by secondary erosion, which raised concerns regarding the introduction of sediment and associated nutrients into the Missouri River.
Soils from nine side-channel chutes were sampled to represent nutrient concentrations from habitat restoration activities. Soils from 12 historically undisturbed sites were also sampled to represent reference conditions in the Missouri River flood plain. The results of this study indicate that nutrient characteristics of soils from selected SWH locations generally are similar to those of historically undisturbed soils. The estimated mass of total phosphorus from chutes accounted for 1.9% of Missouri River and 0.5% of Mississippi River total phosphorus loads during the 1993–2012 analysis period. The mass of nitrate, the constituent most closely related to gulf hypoxia, was 0.01% or less of the Missouri and Mississippi River nitrate loads. Sediment volumes from the chutes accounted for 3.1 and 1.5% of total suspended loads from the Missouri and Mississippi Rivers. Overall, the introduced sediment from side-channel chute construction associated with SWH restoration accounts for a small portion of total nutrient and sediment transport in the Missouri and Mississippi Rivers. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. River Research and Applications published by John Wiley & Sons, Ltd.The Isotope Hydrology of a Large River System Regulated for Hydropowerhttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2740The Isotope Hydrology of a Large River System Regulated for HydropowerC. Soulsby, C. Birkel, J. Geris, D. Tetzlaff2014-03-04T00:14:22.29663-05:00doi:10.1002/rra.2740John Wiley & Sons, Inc.10.1002/rra.2740http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Frra.2740Research Article335349Abstract